Table of Contents
Textures and Microstructures
Volume 30, Issue 1-2, Pages 55-70
http://dx.doi.org/10.1155/TSM.30.55

Features of the Phase Transformations in Sheets, Tubes and Welding Seams of the Alloy Zr–2.5%Nb

Moscow Engineering Physics Institute, Kashirskoe shosse 31, Moscow 115409, Russia

Received 20 February 1997

Copyright © 1997 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

By use of X-ray texture analysis characteristic features of phase transformations in sheets, tubes and welding seams of the Zr–2.5%Nb alloy were studied. Main attention was given to inhomogeneity of phase transformation development, connected with inhomogeneous distribution of strain hardening in grains with different crystallographic orientations. The typical manifestation of phase transformation inhomogeneity in cold-rolled sheets is a shift of the initial texture maximum to the region of increased strain hardening. In channel tubes in consequence of phase transformations αβα the texture component {1120}1010 gains, testifying that tangential stresses favour corresponding alignment of basal normals accompanied by absorption of grains with other orientations. Competition between recrystallization and phase transformation in conditions of heating was considered. As strain hardening increases, recrystallization prior to phase transformation becomes more probable, being predominant within α-grains of some orientations. Parallel development of recrystallization and phase transformation in the zone of thermal influence by arc welding of rolled sheets was considered. It was shown that, as the distance from the melting zone decreases, different combinations of these processes realize.